I've been having the same issues and have gone through all the troubleshooting stuff. Nothing fixes it. There's only one explanation. Verizon is throttling connections to Netflix. More specifically, it's throttling connections to the server infrastructure that Netflix uses, called Amazon Web Services, or AWS.
Go to this web site: http://netneutralitytest.com/
From there, you can run speed tests against some AWS locations, or Linode servers. If you live on or near the east coast, test AWS East, and then test the Linode server closest to you. If you live on or near the west coast, test an AWS server near you, and then a nearby Linode server. I'm on FIOS and paying for 50 Mbit down. When I test AWS East, it starts at 25 and drops steadily to 10. When I test Linode in Newark, NJ I get a constant 57 Mbit.
No way does that make any sense. I'm a software engineer who's been working on server-based software for 7 years, so I'm familiar with the routine of troubleshooting a network connection, and I know some other engineers have posted in this thread.
No way am I paying $60 a month (soon to be $80 since the first year was discounted). I'll cancel the service if it's this bad, I don't care if I have to pay early termination fees. I'll get better service elsewhere.
If you want to know why Verizon is doing this, its because they want you to pay for their TV services instead of getting it from Netflix, Hulu, Amazon and others. A federal court on January 14 ruled that the FCC can't force Verizon and other ISPs to not throttle certain traffic. In other words, a court said Verizon can throttle all it wants and the FCC can't stop them.
http://www.bloomberg.com/news/2014-01-14/verizon-wins-net-neutrality-court-ruling-against-fcc.html
Nobody should be surprised by this, but they should be **bleep** off.